Bearing Reliability Improvement-SKF

2008-10-10 ©SKF

Slide 1 [RS MFC]

SKF [MENA]

Optimising the Performance of Rotating Equipment

- A business case

Mahomed ChothiaManager, Reliability SystemsSKF NV / SA, Brussels

Reliability improvement initiativesMachine Reliability Case StudiesLubrication Management

2008-10-10 ©SKF Slide 2 [Code] SKF [Organisation]

2008-10-10 ©SKF

Slide 3 [RS MFC]

SKF [MENA]

Owning and operating Assets is one of the biggest cost items in a Production Enterprise

Increasing Asset Efficiency is potentially one of the largest sources of profit

Asset Management is much more than Maintenance

Aim: Increased Lifetime Effectiveness &

Return on InvestmentFocus on issues that impact machine

performance and reliability

Asset Efficiency Optimization

2008-10-10 ©SKF

Slide 4 [RS MFC]

SKF [MENA]

Reliability / Maintenance

The purchase price of rotating equipment represents only about 10 to 25 % of its total

cost of ownership,

…. while energy, maintenance and operating costs represent 75 to 90 %.

Source:Lee Culbertson, Royal Purple Ltd., "Justify Lubricant Upgrades with Energy Savings". Machinery Lubrication Magazine. July 2001

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SKF [MENA]

Maximum Efficiency

Operator-Driven Reliability

Pro-Active Reliability Maintenance

Predictive Maintenance

Preventive Maintenance

Reactive/Corrective

Minimum Efficiency

Planning for a shift to an integrated proactive maintenance strategy starts with understanding where you are today in process for maintaining and managing capital assets.

Use a mix of strategies• <10% Reactive• 25% to 35% Preventive• 45% to 55% Predictive

Reliability Focused Maintenance

2008-10-10 ©SKF

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SKF [MENA]

Purchasing

•Ensure product life cycle costs•Increase service level•Quality services•Reduce inventory

PLANT

PERFORMANCE

Management

•Strategy•Business cycles•Shareholder value

Maintenance

•Service response •Perform precision work•Maintain asset•Control costs

Finance

•Budgets•Compliance•Reduce admin costs•Cash flow-ROI

Safety/ Environment

•Reduce emissions•Reduce energy usage•Assure compliance•Avoid hazards

Reliability

•Increase asset efficiency•Increase machine uptime•Reliability systems

Operations

•Increased production•Production quality•Comply w/ maintenance schedules•Cost effective

Engineering

•Re-design current assets•Coordinate maintenance needs•Control projects•Reduce capital outlay.

Who is responsible for Reliability?

2008-10-10 ©SKF

Slide 7 [RS MFC]

SKF [MENA]

Cost of a Production Stop

Steel Mill $10,000 / hour

$10,000 / hour

$15,000 / hour

$100,000 / hour

Millions of $1 stop = 3 to 4 days

$1,000 / hour

Paper Mill

Power Plant (600 MW)

Car Plant (Paint Shop)

Petrochemical

Cement Mill

Food Processing

INDUSTRY COST

2008-10-10 ©SKF

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SKF [MENA]

Asset Efficiency and Machine Reliability

Bearings, seals and other machine components are an essential part of rotating equipment, their reliability is often critical to the plant equipment.

The cost of these components are proportionally very small compared to the maintenance cost of replacement and potential lost production caused by premature failure.

2008-10-10 ©SKF

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SKF [MENA]

Typical Bearing Failures

Premature Fatigue 34%

Poor fitting 16%

Poor lubrication 36%

Contamination 14%

2008-10-10 ©SKF

Slide 10 [RS MFC]

SKF [MENA]

Bearing Failure Analysis

23280 CCK/C3 W33

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SKF [MENA]

Predictive Maintenance Techniques - Typical

Condition Monitoring helps determine the deteriorating condition of a machine component, in advance of a breakdown. (Proactive Maintenance)

Typical machinery parameters measured, trended and analysed to detect imminent failure or onset of problems:

• Machinery vibration • Lube oil analysis including wear debris analysis • Infrared thermography• Ultrasonic testing • Motor current analysis • Alignment

Additional parameters such as flow rates, temperature, pressure, speed etc. can be monitored to detect problems. The techniques used depends on the criticality of the

equipment.

2008-10-10 ©SKF

Slide 12 [RS MFC]

SKF [MENA]

Various studies reveals some interesting statistics:

• Between 20% to 70% of maintenance currently undertaken is reactive in nature. Reactive maintenance is typically 10x more expensive than predictive maintenance [8].

• The direct cost of repairs undertaken on a breakdown basis is typically three times the cost of planned repairs.

• Production outage time needed for completion of an emergency repair can be shown to be between three and five times that needed if the repair was carried out on a planned basis.


2008-10-10 ©SKF

Slide 13 [RS MFC]

SKF [MENA]


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SKF [MENA]

• Maintenance • Reliability

Asset Management

Survey results Best Practice

55% is Reactive < 10 %31% Preventive 25 – 35%12% Predictive 45 – 55%- Proactive 20%2% as other

Source: SMRP (Society of Maintenance & Reliability Professionals) survey.

Asset Efficiency Optimization

2008-10-10 ©SKF

Slide 15 [RS MFC]

SKF [MENA]

World Class AverageAverage life of electric motors > 15 yrs < 10 yrs

Mean time between repairs for pumps > 6 yrs < 3 yrs

Average machine vibration levels (mm/s) < 2 to 5 > 5

Reliability advantages are well known

An effective maintenance program has many benefits.

• Return on investment: 1 : 10 • Reduction in maintenance costs: 25 to 30 %• Elimination of breakdowns: 70 to 75 %• Reduction in downtime: 35 to 45%• Increase in production: 20 to 25 %.

2008-10-10 ©SKF

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SKF [MENA]

Stock Optimisation

Problem descriptionMRO stock is a large part of the maintenance budget Approximately 15 to 25%

Implemented solutionStores Audits and RecommendationsInventory management Stock optimization - (criticality, spares cost and availability) Storage, Handling, Obsolescence.

Resulting benefitsReduced stock, better availability, correct items

Savings generatedPotential estimated - 100 000 Euro

Bearing Technology Machine Reliability


2008-10-10 ©SKF

Slide 18 [RS MFC]

SKF [MENA]

Rotating Equipment Reliability

• Root Cause Failure Analysis• Application analysis• Mechanical Design • Machine Upgrade• Technology Upgrades

Design review aimed at evaluating applications, then recommending and implementing design improvements to extend machine life.

Machine Improvements

2008-10-10 ©SKF

Slide 19 [RS MFC]

SKF [MENA]

Bearing Life – Influence of load

A 20% load increase reduces the calculated bearing life by half

L10h = 1,000,000 x (C/P)p(60 x n)

2008-10-10 ©SKF

Slide 20 [RS MFC]

SKF [MENA]

Sealed Spherical Roller Bearings

Regreasing bearings used to present serious problems.

Heat of the casting process caused the bearing grease to melt and blend with the cooling water.

Grease used: 16 tons/yr.

By installing sealed spherical roller bearings, which do not need to be regreased, the problems have been reduced substantially. Savings (grease): Euro 60,000

* Other savings not considered

Caster Bearings in Steel Mill

Machine Reliability Improvements Case Studies


2008-10-10 ©SKF

Slide 22 [RS MFC]

SKF [MENA]

- design review- shaft repair / machining tolerances- sealing arrangement- condition monitoring- lubrication selection

Electrical Motor Reliability

2008-10-10 ©SKF

Slide 23 [RS MFC]

SKF [MENA]

Electrical Motors

SKF Reliability Maintenance Institute

Typical failure modes:Bearings 40%Stator 30%Rotor 8%Others 22%

Poor power quality

Insulation failure

Excessive current

MisalignmentUnbalanceSoft footBearingsLubricationOverheating

mechanicalelectrical

2008-10-10 ©SKF

Slide 24 [RS MFC]

SKF [MENA]

Electrical Motors – Lubrication Program


Conversion from pure mist lubrication to grease lubrication. High Voltage Motors

Motor population: about 10060% converted to grease.

Refinery – Middle East

Savings / Benefits

Elimination of oil mist system and associated maintenanceSimplified lubrication proceduresImproved environment / health

2008-10-10 ©SKF

Slide 25 [RS MFC]

SKF [MENA]

Reliability Improvement in Large Electrical Motors


Motor in Steel MillReference case: SIEMENS

Common to use sleeve / plain (hydrodynamic) bearings. Can be expensive if it includes; extra oil pressure systems for low or reversing speeds. Oil Circulation required to control temperature.

Rolling Bearing offer an advantage compared to sleeve bearings. Initial Cost savings 30%. + Lower life cycle cost

Flanged Bearing Unit

2008-10-10 ©SKF

Slide 26 [RS MFC]

SKF [MENA]

Electric Motor - Machine Reliability

A European company, faced high maintenance and material costs due to electrical current damage to critical electric motors.

Standard ball bearings lasted about 6 months

To reduce costs and to achieve reliable operation INSOCOAT® bearings were used. Since 1995 there have been no bearing failures.

Flue Gas Recirculation Fan Motor

Financial outcomeInitial investment 5,000 EuroTotal savings 250,000 Euro

2008-10-10 ©SKF

Slide 27 [RS MFC]

SKF [MENA]

Centrifugal Pump Reliability

2008-10-10 ©SKF

Slide 28 [RS MFC]

SKF [MENA]

Average cost of repair $6,000 / pump

Given the number of pumps in operation the cost savings are substantial

Typical failure are due to:Mechanical seal, bearing, lubrication

Premature failures

Centrifugal Pumps

Bearings - Angular Contact Ball Bearing, universal pairingImproved lubrication – synthetic lubricant Sealing arrangement - mechanical seals, isolators

2008-10-10 ©SKF

Slide 29 [RS MFC]

SKF [MENA]

Process Pump

Matched bearings are best suited for pumps.Usually fitted in a back-to-back arrangement (without the use of shims)

SKF “BECB” bearings have the correct axial clearance after mounting.

BG =“BECB”P6 runout

± 3 microns

2008-10-10 ©SKF

Slide 30 [RS MFC]

SKF [MENA]

Process Pump

API 610 standard for refinery service pumps specify bearings with machined brass cage

eg.: 7218 BECBM

B – 40 degree contact angleE – High load carrying capacity

CB – Clearance classM – Brass cage

Correct choice of shaft and housing fits is essential for reliability

2008-10-10 ©SKF

Slide 31 [RS MFC]

SKF [MENA]

Case study – Centrifugal Pump

Application:Horizontal centrifugal pump (6 off)Speed: 3600 rpmPower: 75 kWOil bath lubrication (ISO VG 68)- oil pick-up ring

Problem:Premature failures: 3to 4 months

Investigation revealed the following:Incorrect bearingsIncorrect fit on shaftLubricant supply to the bearings

Reverse Osmosis Plant

2008-10-10 ©SKF

Slide 32 [RS MFC]

SKF [MENA]

Exhaust FanReliability improvement project

- design review and engineering - design of new components- shaft repair and impeller balancing- Installation and commissioning- lubrication selection

2008-10-10 ©SKF

Slide 33 [RS MFC]

SKF [MENA]

Exhaust Fan – case study

High impact on production !Proposal to convert the plain bearings to Rolling Bearings.

Cooler Scrubber Exhaust Fan

• Power: 320 kW

• Speed: 890 rpm

• Lubrication: Oil circulation

• Sleeve bearings

• Operating temperature: 93 ºC

• Year installed: 1990

• Mean Time Between Failure: 3 to 5 months

2008-10-10 ©SKF

Slide 34 [RS MFC]

SKF [MENA]

Exhaust Fan

Electric Motor

2008-10-10 ©SKF

Slide 35 [RS MFC]

SKF [MENA]

Exhaust Fan - failure

Damage to sleeve bearing

Damage to shaft and thrust collar

2008-10-10 ©SKF

Slide 36 [RS MFC]

SKF [MENA]

Exhaust Fan – Solution

Customized solution using CARB and SRB + SONL Housing

Customer Benefits • Lower bearing temperature 60° C vs 90° C • Reduced current drawn by motor (- 5 Amps)• Simplified lubrication system

- (oil circulation not required)• Lower vibration levels• Improved reliability


Exhaust Fan - Savings (Estimated)

Energy savings: $ 3,000 / fan / yrLubrication: $ 2,500 / yearMaintenance / Labour: $ 3,400 / failureLost Production: $ 40,500 / dayCost of shaft repair: $ 15,000

Plain Bearing Failures ……..Time to repair shaft / balancing 4 daysRebabbitting of bearings 1 dayInstallation / commissioning 1-2 days

Failure of plain bearings 3 – 5 monthsNew SKF solution > 33 months *• first fan commissioned mid Feb 2005

SAVINGS: > $ 360,000 /yrSecond fan commissioned end Sep 2006

2008-10-10 ©SKF

Slide 38 [RS MFC]

SKF [MENA]

High Speed Fans

For high speed applicationsFan Unit Housing Assembly improves reliability

Plummer blocks Ready to mount unit

2008-10-10 ©SKF

Slide 39 [RS MFC]

SKF [MENA]

Bearing Failure Analysis – Steel Mill

Low MTBF of the bearings.Cracking of the outer ring (some) Premature flaking.

PROBLEMDESCRIPTION

Few monthsService Life:

High operating temperature. High humidityEnvironment:

Grease EP2Lubrication:

SKF 24148 CC/C2.W33/235220OEM BearingDesignation

SKF 24148 CC/C2.W33BearingDesignation

Rolling Mill - Stands 1 and 2Equipment:

2008-10-10 ©SKF

Slide 40 [RS MFC]

SKF [MENA]

Bearing Failure Analysis

Root Cause Failure Analysis • Entry of water and contaminants • Incorrect fits / geometric form tolerances of the housing seating• Lubrication type and method

Savings: EURO 250,000 – Elimination of premature failures


Paper Mill

Press Roll Section

Reliability Improvement Project

2008-10-10 ©SKF

Slide 42 [RS MFC]

SKF [MENA]

Customer requirements:Improve reliability of the press section. Increase speed of the machine and production.Solution:Improved design of the housing / bearing assembly –10 housings, oil circulation system, sealing arrangement.

• Root cause failure analysis• Optimized housing design (stiffness) • Improved sealing arrangement• Oil circulating system

Customer benefits: Improvements to the machine performanceFinancial savings – uptime, increased MTBF

Paper Mill (Egypt),

Press Roll Upgrade Project

23280 CCK/C3 W33

2008-10-10 ©SKF

Slide 43 [RS MFC]

SKF [MENA]

Before - Premature bearing failures each 8 months. After implementation of the improved solution –Bearing life was extended to more than 20 months.

Time required to change the bearing: 36 hoursThe manpower cost: Euro 2,500Production: 9 tons/ hour. Price of one ton of paper: EURO 650

Financial calculation - Cost Savings1- Number of tons lost due to 1 break down = 9 x 36 = 324 tones2- Cost of production lost = 324 x 650 = Euro 210,6003- Total cost of one break down = 210,600 + 2500 = 213,1004- No. of break downs avoided = 20/8 = 2.5

Total cost saving (improved reliability – avoidance of breakdown)

= 2.5 x 213,100 = Euro 532,750

Paper Mill - Press Roll Upgrade Project

2008-10-10 ©SKF

Slide 45 [RS MFC]

SKF [MENA]

Lubrication Management - Why?

Contamination reduces machine reliability and causes bearing / component failures

Best Practice in Lubrication Management

ReasonsContaminated environmentContaminated lubricantsIneffective sealsComponent wear

Corrective ActionsContamination free systemsTraining in lubricationCleaner work areas Use of oil filtration / breathersRedesign the sealing arrangement

2008-10-10 ©SKF

Slide 47 [RS MFC]

SKF [MENA]


Contaminants cause wear to components in machinery

Contamination in new oil

2008-10-10 ©SKF

Slide 48 [RS MFC]

SKF [MENA]

Failed Bearing - Lubricant Analysis

Fresh: Brown colourUsed: Yellow colour

Water in the lubricant

2008-10-10 ©SKF

Slide 49 [RS MFC]

SKF [MENA]

Water concentration in a stationary bearing

Deep-seated rust during stand-still conditions

Lubrication – Water Content

2008-10-10 ©SKF

Slide 50 [RS MFC]

SKF [MENA]

Lubrication – Water Content

0%

50%

100%

150%

200%

250%

50003000 45002500 40002000 350015001000500

Rated Bearing Life

Water in Oil (ppm)

Based on 100% Life at 100ppm water

Effect on bearing lifeMaximum of 200 ppm

1 ppm = 1 mg / kg

New lubricant guideline25 ppm at 20 C

2008-10-10 ©SKF

Slide 53 [RS MFC]

SKF [MENA]

Best Practices, Transfer Containers

Oil Safe®

Lubrication System

Protect Lubricants from Contamination

Reduce Machinery Downtime

Minimize Spills & Accidents

10 Colors to Code Lubricant Grades

Reliability improvement initiativesMachine Reliability Case StudiesLubrication Management


Thank you

Bearing Reliability Improvement-SKF

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